Throttle control systems for engines driving forward and reverse gears



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July 12, 1960 THROTTLE CONTROL SYSTEMS FOR ENGINES DRIVING FORWARD AND'REVERSE GEARS 5;: 55? E v N \1 x =8 $22 3 SE 0 5 233% o 0 THRO'ITLE CONTROL SYSTEMS FOR ENGINES DRIVING FORWARD AND REVERSE GEARS Basil Gervase Markham, Bristol, England, assignor, by mesne assignments, to Bristol Aero-En'gines Limited, Bristol, England, a British company This invention relates to a throttle control system for engines driving forward and reverse gears and concerns United States e fi Q such engines driving'forward and reverse gears-includ- 1 ing forward and reverse clutches.

The main object the invention is to' provide such engines with safety means, whereby the throttle of the engine cannot respond to a manual throttle control until the forward or the reverse clutchhas been engagedor T made effective.

According to the invention, there is provided for an engine driving forward and reverse gears including forward and reverse clutches, a throttle control system comprising a manual control for the throttle, means for actuating the forward and reverse clutches, and means for delaying the opening of the throttle inresponseto movement of the manualthrottle control to open the throttle until the said acuating means'hascaused'either one of said clutches to become engaged. The manual throttle control may be arranged to control said actuating means so that movement of said manual throttleeontrol to open the throttle in an ahead range first causes the forward clutch to become engaged, and movement of said This may be doneeither by interlocking the throttle control and the gear control, or by providing a single lever to control both throttle and gear. F 1

The control system is especially, but'not' exclusively, applicable to a reverse reduction gear of the epicyclic type and by way of example the -invention is hereinafter described with reference to the accompanying drawing which shows in diagrammatic form a hydraulic poweroperated control system for a marine engine.

The marine engine is adapted to drive a screw propeller'shaft through an epicyclic reverse-reduction gearbox. From the neutral position of the gears, ahead or manual throttle'control to open the throttle in an astern 14 1 range first causes the reverse clutch to become engaged.

astern is selected by the hydraulic application of a clutch I '11, and a connecting rod 70 to a rocking arm =12, one end of which isattached to a servo piston 13 controlling the throttle linkage 14 and the other end is attached to a servo-valve 15 controlling the supply of oil to one side of the servo-piston 13. The bell crank lever 11 is se cured to a shaft 16 on which are mounted two supply valves 17 and 18, the former valve'17being arranged fto control the supply of oil to either of thejoperating pistons 19, 20 for actuating the astern or ahead clutches,

and the latter valve 18 being arranged to permit oil to reach the servo mechanism for the throttle. The ser'ivo cylinder 29 houses a servo piston 13 connected ,to the throttle linkage 14 and controlled by a spring 21 which moves the piston to cause the throttle linkage to close the throttle, the spring 21 being housed in the cylinder 29 on one side of the piston 13 on a spaceve'nted to atmosphere by means of a vent 71. A servo valve 15 2,944,645 Patented July 12, 19 60 slides in a'chamber 22provided with a pressure equalising duct 23, two ports 24, 25 and a restrictor or passage 26 whichre'stricts flow. The servo valve 15 controls the supply of oil through the restrictor 26 and port 24 to the servo cylinder 29, and also controls the passage of oil escaping from the servo cylinder through ports 24 and 25 when the throttle setting is reduced. A non return ball valve 27 permits the oil to drain from the servo cylinder 29 when the oil pressure in the passage 28 drops. p l

The connecting rod 70 which connects the bellcrank lever:11 to the rocking arm 12 is arranged to be in line with the arm of the bellcrank lever to which it is connected when the throttle control 10 is in its neutral position. In this manner it is ensured that when the throttle.

control. 10 is moved from its neutral position to select either ahead or astern the rocking arm is pivoted about its connection with the .servo piston 13 to displace the valve -1'5 to the right in the drawing; 7 v

In operation, the throttle control 10, which may be located on theships bridge, may be moved from neutral to ahead; This movement is transmitted to' the bell crank lever 11 causing it to rock and rotate the shaft '16 in one direction. Rotation of the shaft in this direction causes the valve 17 to open and permit oil under pressure to flow to the operating chamber of the piston 20 for actuating the ahead clutch and also causes the valve 18 to open and permit oil to flow to the restrictor 26. Further movement of the throttle control 10 to preselect adefinite throttle setting is transmitted through the rocking arm 12 to cause the servo valve 15 to move toithe right in the drawing and permit passage of oil from the restr'ictor 26to the port 24 and thence into the servo cylinder 29. v

' The oil pressure in-the operating chamber 30 builds up rapidlyand displaces the, operating piston 20 so as to engage the clutch. As soon as this pressure has been achieved, the oil forcing past the delaying restrictor 26 and intothe servo cylinder 29 is able to build up and displace the servo piston 13to the right in the drawing. Displacement of the servo piston 13 pivots the rocking arm 12 about its connection with the connecting rod 70 and consequently the valve 15 is moved to the left in the drawing. Movement of the servo piston 13 ceases as soon as the valve 15 reaches its equilibrium'position in which it closes the port 24 and it will be seen therefore that the extent of movementof the servo piston brought about by adjustment of the throttle control 10 depends on the amount by which the throttle control 10 is moved. The displacement of the servo piston 13 actuates the throttle linkage 14 to open the throttle to the amount pre-selected by the setting of the throttle control '10. The spring '21 is of such strength as to ensure that the throttle will not open until the'oil pressure is suflicient to engage the clutch. It will be noted that the restrictor '26 also controls the rate of opening of the throttle so as to avoid the stalling of the engine, particularly a gas turbine engine.

If now the throttle settlng is reduced, that is to say,

if the throttle control 10 is moved back towards its moved-to the left in the drawing by the spring 21, and

the throttle ppeningis' reducedby an amount correspon dingto' tlie' movement of thethrottle control 10,-the

movement of the servo piston to the left in the drawing ceasing when the valve 15 again reaches its neutral position in which it covers the port 24. When the throttle control is moved right back to its neutral position the valve 15 is again displaced to the left in the drawing uncovering the port 24 to drain, and the servo piston is displaced to the left in the drawing by the spring 21, the movement of the servo piston closing the throttle, whereupon the movement of the piston ceases. In this case the valve 15 follows up the movement of the servo piston but does not return completely to its equilibrium position but to the position shown in the drawing.

When the throttle control It is moved to astern and then to a pro-selected setting, the valve 17 is opened so as to permit the oil to flow to and displace the operating piston 19 of the astern clutch, the valve 17 at the same time placing the operating chamber 30 in communication with a drain passage 74, the valve 18 is opened to permit oil to flow to the restrictor 26, and the servo valve 15 is moved to permit passage of oil from the restrictor 26 to the port 24 and thence into the servo cylinder 29. As soon as the operating chamber 30 is placed in communication with the drain passage 74 the oil pressure in the chamber 30 is relieved and the forward clutch is disengaged. At the same time oil pressure is built up in the operating chamber 75 of the piston 19, and the astern clutch engaged. After the oil pressure has been built up in the operating chamber 75 and the astern clutch engaged the oil is able to displace the servo piston 13 and cause the throttle to be opened to the amount pre-selected by the setting of the throttle control 10.

In the neutral position of the throttle control said predetermined hydraulic pressure has been exceeded.

the valve 17 places each of the operating chambers releasing the spring 21 to cause the servo piston 13 to return and close the throttle. The invention therefore prevents the engine from overspeeding when a clutch becomes disengaged due to a failure in the oil pressure. The system according to the invention also makes it impossible to overspeed the engine by opening the throttle with the gear in neutral.

In the example being described, the throttle linkage is provided with a limited control for slow-running and stopping which is independent of the servo control mechanism and normal throttle control. This limited control comprises a collar 3-3 or stop on the throttle linkage 14 which is engageable by a pivoted control arm 34 operated by a control lever 35 in the engine room control station. By this means the throttle may be opened toa limited extent, without previously engaging either clutch, for inspection and testing purposes.

I claim:

1. A throttle and transmission control system comprising in combination; a source of hydraulic power; a first hydraulic clutch motor; a second hydraulic clutch motor, which clutch motors are independently connected to said source to be operated by a predetermined hydraulic pressure, selector valve means for connecting one of said clutch motors selectively to said source, a hydraulic throttle motor for operating a throttle and comprising a piston and cylinder; conduit means connecting said source and said cylinder so that the piston tends to move in one direction on increase of hydraulic pressure, said conduit means also connecting said cylinder to the said one of the clutch motors and a preloaded spring between said piston and said cylinder and opposing relative movement between said piston and said cylinder in said one direction, said spring being preloaded to an extent such that said piston moves relative to said cylinder only after '2. A throttle and transmission control system comprising in combination a source of hydraulic power; a first hydraulic clutch motor; a second hydraulic clutch motor; a hydraulic throttle motor for opening a throttle and comprising a piston and cylinder; a conduit leading to said cylinder on one side of said piston; spring means acting on the other side of said piston and being preloaded to an extent such that the piston moves relative to the cylinder only after a predetermined pressure has been exceeded; progressively operable servo-valve means in said conduit; control valve means operable to selectively connect said source to one of said clutch motors and to connect said conduit to said one of said clutch motors; a manually operable member; and a mechanical linkage connecting said manually operable member to both said servo-valve means and said control valve means.

'3. A throttle .and transmission control system as claimed in claim 2 in which the manually operable member is pivotable in a clockwise and an anti-clockwise direction from an initial position and said control valve means comprises a rotary valve rotatable by said manually operable member to connect said first hydraulic clutch motor to said source when the said manually operable member is pivoted in a clockwise direction from the initial position, and to connect said second hydraulic "clutch motor to said source when said manually operable member is pivoted in an anti-clockwise direction from the initial position.

"4. A throttle and transmission control system as claimed in claim '3 in which the linkage comprises a bell crank lever having two mutuallyinclined arms radiating from a central part and being mounted to pivot about afirst axis, first link means pivoted to one arm of said bell crank lever connecting said one arm to said manually operable'member, second link means connected to said control valvemeans and a connecting link connected at one end thereof to the other arm of said bell-crank lever to pivot about a second axisand at its other end to'said second link means to pivot about a third axis, the first, second and third axes lying in a common plane when said manually operable member is in its initial position.

5. A throttle and transmission control system comprising in combination a source of hydraulic power; a first hydraulicclutch motor; a second hydraulic clutch motor;

- a hydraulic throttle motor for opening a throttle and comprising a piston and cylinder; a first conduit leading to'said cylinder on one side of said piston; spring means acting on the other side of said piston and being preloaded to an extent such that the piston moves relative to the cylinder only after a predetermined pressure has been exceeded; a vent leading from said cylinder on said-one side of said piston; a second conduit leading from said vent; pressure release valve means operable to connect said vent to said second conduit when the pressure in said second conduit falls below said predetermined pressure; and control valve means operable selectively to connect said source with one of said hydraulic clutch motors to connect said first conduit to said one of said clutch motors and to connect said second conduit directly to said source and to said one of'said clutch motors.

References-Cited in the file of this patent UNITED STATES PATENTS 2,321.098 

